"Let it be one cheerful rational voice amidst the din of mourners and polemics." Ralph Waldo Emerson, 1840.
A Brit-in-Helsinki's blog about global politics, climbing, cycling, things that annoy me and other bits of life. But not necessarily in that order.

Friday, July 20, 2007

Floods

This house should not be in a lake. Photo taken by my dad and submitted to the BBC Hereford and Worcester website.

Much of England, where I currently am, is suffering from torrential rain that is leading to serious flooding. My family home is on the top of a hill and therefore probably about the least likely place to get flooded in the county, and it wasn't until we left the house to drive to the nearest town to do some shopping that we realised just how bad it was getting. We gave up on going shopping after seeing some neighbours out in front of their houses digging ditches trying to divert water flowing towards their property off the flooded roads and fields. I took my family back to my parents' house and then dressed in full waterproofs and wellies, grabbed a spade and headed down the hill to see if I could help out. We lugged sandbags and built small walls to divert the water, tried to keep the drains cleared, and dug ditches trying to get the water around the houses and down a track into the fields behind. It seemed to be working and as long as the drains don't block with silt off the fields it is probably only going to ruin peoples gardens, rather than actually getting into their houses. One couple hadn't even moved back in, and were living with relatives, since their ground floor was flooded out a month or so ago in the last round of flash flooding.

I lived here for about 15 years of my life until I went to University, but have continued to regularly visit as my parents still live in in the same house, and I don't think in just under 30 years I have ever seen these particular houses just down the hill from us threatened by flooding. And in the summer as well?! Of course it is impossible to say "this is climate change then!", as all sensible climate scientists say all they can really talk about is trends. But the climate models suggest that the UK is going to get stormier and have more extreme weather events - like the short period of intense rain (on already soaked ground) - like we've seen today. If I move back to the UK I will buy a house on a hill!

The film clips below are of a nearby mill, down the other side of the hill. This absolutely beautiful house has been empty since a man house-sitting for the owners had to be rescued by the Fire Service in last month's floods. It got so serious a helicopter was called in although fortunately local fire fighters got to him first. The first film I took around 3 pm; my dad took the second a couple of hours later and the water has clearly risen around a meter.

The Thames froze over because the old London Bridge impeded the flow - this is why it hasn't frozen over since despite the coldest winters on record occurring after its removal.

There are more vinyards in the UK now than in the climatic optimum of the Middle Ages. Relatively less trade and availability of wine in the past made vineyards in marginal climates (and therefore with marginal quailty wine) possible.

More seriously, there has been remarkably little analysis of why this summer has been so wet, beyond catch-all claims of global warming. (Although I read a comprehensive article on a press association wire about it a month ago that pretty much nailed it, although I never saw it in press anywhere, which sort of tells you how the UK media treats 'science stuff'.)

They quote the Met Office and put the wet summer down to La Nina, sister to El Nino. In short, this is thought to have shifted the jet stream over Europe by about 400miles south. So we are getting weather that should be over the Orkneys and Iceland.

This is why we keep hearing 'More rain on the way'. We have very moist, low pressure systems sweeping across the UK at the height of summer. The strong sun heating the ground creates strong convection, which is why we have had a summer of storms and very heavy downpours.

If the air masses change to dryer air, and the land gets to dry out a bit (eg if high pressure asserts itself), then we may see the convection calm down and and the storms cease - less moisture in the ground means less in the air and less to come back down in the afternoon. If however, the land stays wet, the air masses stay moist and the pressure low, then the only thing that will stop the cycle is a reduction in sun strength - ie the end of summer.

The jet stream will eventually shift back to a more 'normal' pattern, and more normal weather systems will reassert themselves again, so don't worry, it's just a very wet summer. We've had them before, albeit not very often within living memory.

The issue of land use, flood defences, the politics behind planning for 100-year events and the like are of course different.